The effect of HPMC and MC as pore formers on the rheology of the implant microenvironment and the drug release in vitro

Arboviral diseases are a threat to global public health systems, with recent data suggesting that around 40% of the world’s population is at risk of contracting arboviruses. The use of mosquito repellents is an appropriate strategy to avoid humans coming into contact with vectors transmitting these viruses. However, the cost associated with daily applications of repellents can make their use unfeasible for the low-income populations that most need protection. Therefore, the development of effective formulations offers a way to expand access to this means of individual protection. Consequently, research efforts have focused on formulations with smaller quantities of active agents and sustained release technology, aiming to reduce re-applications, toxicity, and cost. The present study investigates the development of nanostructured lipid carriers (NLCs) loaded with a mixture of the compounds icaridin (synthetic) and geraniol (natural), incorporated in cellulose hydrogel. The NLCs were prepared by the emulsion/solvent evaporation method and were submitted to physicochemical characterization as a function of time (at 0, 15, 30, and 60 days). The prepared system presented an average particle size of 252 ± 5 nm, with encapsulation efficiency of 99% for both of the active compounds. The stability profile revealed that the change of particle size was not significant (p > 0.05), indicating high stability of the system. Rheological characterization of the gels containing NLCs showed that all formulations presented pseudoplastic and thixotropic behavior, providing satisfactory spreadability and long shelf life. Morphological analysis using atomic force microscopy (AFM) revealed the presence of spherical nanoparticles (252 ± 5 nm) in the cellulose gel matrix. Permeation assays showed low fluxes of the active agents through a Strat-M® membrane, with low permeability coefficients, indicating that the repellents would be retained on the surface to which they are applied, rather than permeating the tissue. These findings open perspectives for the use of hybrid formulations consisting of gels containing nanoparticles that incorporate repellents effective against arthropod-borne virus. These systems could potentially provide improvements considering the issues of effectiveness, toxicity, and safety.

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“…Furthermore, HPMC provides film formation increasing the surface area available for permeation (Aho et al, 2017).…”

Section: In Vitro Permeation Profilesmentioning

confidence: 99%

Development of a Mosquito Repellent Formulation Based on Nanostructured Lipid Carriers

et al. 2021

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“…55 Besides contributing to the drug release profile, the incorporation of pore formers into the polymeric matrix was also found to affect the rheology of the surrounding biological fluids. Using water-soluble polymers methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) as pore formers and nitrofurantoin (antibiotic) as the model drug, Aho et al 56 demonstrated that HMPC pore formers had a higher impact on the surrounding viscosity, with higher drug release and pore forming ability in vitro when compared to the MC pore formers. The highest increase in the viscosity of the microenvironment was achieved with the highest molecular weight HPMC while the highest drug release was obtained with the lowest molecular weight HPMC, suggesting that the microenvironment rheology (both in the formed pores and in close surrounding biological fluids) can affect drug diffusion from the polymeric matrix.…”

Section: ■ Release-based Antimicrobial Strategiesmentioning

confidence: 99%

A Glance at Antimicrobial Strategies to Prevent Catheter-Associated Medical Infections

et al. 2020

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Urinary and intravascular catheters are two of the most used invasive medical devices; however, microbial colonization of catheter surfaces is responsible for most healthcare-associated infections (HAIs). Several antimicrobial-coated catheters are available, but recurrent antibiotic therapy can decrease their potential activity against resistant bacterial strains. The aim of this Review is to question the actual effectiveness of currently used (coated) catheters and describe the progress and promise of alternative antimicrobial coatings. Different strategies have been reviewed with the common goal of preventing biofilm formation on catheters, including release-based approaches using antibiotics, antiseptics, nitric oxide, 5-fluorouracil, and silver as well as contact-killing approaches employing quaternary ammonium compounds, chitosan, antimicrobial peptides, and enzymes. All of these strategies have given proof of antimicrobial efficacy by modifying the physiology of pathogens or disrupting their structural integrity. The aim for synergistic approaches using multitarget processes and the combination of both antifouling and bactericidal properties holds potential for the near future. Despite intensive research in biofilm preventive strategies, laboratorial studies still present some limitations since experimental conditions usually are not the same and also differ from biological conditions encountered when the catheter is inserted in the human body. Consequently, in most cases, the efficacy data obtained from in vitro studies is not properly reflected in the clinical setting. Thus, further well-designed clinical trials and additional cytotoxicity studies are needed to prove the efficacy and safety of the developed antimicrobial strategies in the prevention of biofilm formation at catheter surfaces.

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“…In vitro release study Figure 5 shown the release of the drug in simulated gastrointestinal conditions (pH1.2; pH6.8; pH7.4) during the study period. HPMC as a water-soluble material, the solubility also well in the stomach pH value (pH 1.2) (Cole et al, 2001;Aho et al, 2017). HPMC could be quickly dissolved in the stomach, so that the drug could be released rapidly from the pellets to achieve the efficacy.…”

Section: 3mentioning

confidence: 99%

Preparation and evaluation of Vinpocetine self-emulsifying pH gradient release pellets

et al. 2017

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The main objective of this study was to develop a pH gradient release pellet with self-emulsifying drug delivery system (SEDDS), which could not only improve the oral bioavailability of Vinpocetine (VIN), a poor soluble drug, but reduce the fluctuation of plasma concentration. First, the liquid VIN SEDDS formulation was prepared. Then the self-emulsifying pH gradient release pellets were prepared by extrusion spheronization technique, and formulation consisted by the liquid SEDDS, absorbent (colloidal silicon dioxide), penetration enhancer (sodium chloride), microcrystalline cellulose, ethyl alcohol, and three coating materials (HPMC, Eudragit L30D55, Eudragit FS30D) were eventually selected. Three kinds of coated pellets were mixed in capsules with the mass ratio of 1:1:1. The release curves of capsules were investigated in vitro under the simulated gastrointestinal conditions. In addition, the oral bioavailability and pharmacokinetics of VIN self-emulsifying pH gradient release pellets, commercial tablets and liquid VIN SEDDS were evaluated in Beagle dogs. The oral bioavailability of self-emulsifying pH gradient release pellets was about 149.8% of commercial VIN tablets, and it was about 86% of liquid VIN SEDDS, but there were no significant difference between liquid SEDDS and self-emulsifying pH gradient release pellets. In conclusion, the self-emulsifying pH gradient release pellets could significantly enhance the absorption of VIN and effectively achieve a pH gradient release. And the self-emulsifying pH gradient release pellet was a promising method to improve bioavailability of insoluble drugs.

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The effect of HPMC and MC as pore formers on the rheology of the implant microenvironment and the drug release in vitro

Cited by 13 publications

References 53 publications

Development of a Mosquito Repellent Formulation Based on Nanostructured Lipid Carriers

Development of a Mosquito Repellent Formulation Based on Nanostructured Lipid Carriers

A Glance at Antimicrobial Strategies to Prevent Catheter-Associated Medical Infections

Preparation and evaluation of Vinpocetine self-emulsifying pH gradient release pellets

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